The inventions described below relate the field of cryosurgery and the treatment of breast disease.
The methods and systems described below provide for optimal treatment of fibroadenomas. A fibroadenoma is a benign tumor found in women""s breasts. They are small, solid, round, rubbery masses that are typically found in breast self-exams or mammography. Fibroadenomas are harmless, but may be painful, palpable and emotionally bothersome, and the may mask other lesions that would otherwise be visible to mammography. Fibroadenomas are removed to alleviate pain and to alleviate the emotional burden of living with a breast lump. Even when the breast lump is confirmed to be a benign fibroadenoma, many women elect removal for these reasons. Typically, fibroadenomas are removed by lumpectomy, which is an open surgical procedure. Open surgical recision requires a fairly large incision, creates an unsightly scar on the breast and a scar inside the breast that interferes with mammography, and it requires general anesthesia.
Sanarus, Inc. has proposed cryoablation of fibro-adenomas in its PCT publication WO0197702. As proposed in that publication, cryoablation entailed the commonly preferred double freeze-thaw cycle consisting of a 6 to 15 minute freezes followed by thawing until the internal cryoprobe temperature reaches 0xc2x0 C. While that procedure is useful, the procedure described below provides suitable treatment with the advantages that a smaller iceball is created, it avoids ablating tissue surrounding the fibroadenoma that need not be ablated given the benign nature of the fibroadenoma, it limits the potential for damage to the skin overlying the fibroadenoma, and the resorption time for the ablated mass is greatly reduced.
The methods and systems described below permit treatment of fibroadenomas with a minimally invasive cryosurgical procedure. The procedure entails use of a cryoprobe to cryoablate a fibroadenoma. Cryoablation is performed with a period of high power freezing, followed by a period of low power freezing, followed by a period of thawing, and a repetition of high power freezing and low power freezing, followed by thawing and/or warming of the cryoprobe. When accomplished with commercially available cryoprobes such our new Visica(trademark) cryoprobes, which are adapted for partial duty cycle operation, the method entails a period of full power freezing, followed by a period of low duty cycle freezing, followed by a period of thawing, followed by a repetition of these steps.
Performance of the method is facilitated by a control system that allows a surgeon or technician to enter desired periods of full power freezing and reduced power freezing. The desired time for full power and reduced power freezing is selected based on the size of the fibroadenoma and empirical experience, and may be preprogrammed into the system control box. After entry of these parameters, the system operates automatically to apply cooling to the fibroadenoma as desired by the surgeon. The progress of the cryosurgery may be monitored with ultrasound and thermocouples.